作者: Masakazu Tane, Soong Keun Hyun, Hideo Nakajima

摘要: We studied the effective electrical conductivity of lotus-type porous nickel with cylindrical elongated pores by applying the extended effective-mean-field (extended EMF) theory that is based on Hatta-Taya’s theory and Bruggeman’s effective-medium approximation. We modeled lotus-type
porous nickel as the composite materials with ellipsoidal void inclusion, and examined the effect of shape and orientation of the pores and applied-electric-field direction on the effective electrical conductivity. The extended EMF theory revealed that well-known Archie’s power law is quite useful for expressing the porosity dependence of the electrical conductivity of lotus-type porous metals even
though the deviation of porous morphology exists.

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作者: Thomas Fiedler, Andreas Öchsner, Nilindu Muthubandara, Irina V. Belova, Graeme E. Murch

摘要: In this paper, the Finite Element and lattice Monte Carlo methods are used to calculate
the effective thermal conductivity of two models of a composite: circular and square inclusions
arranged in a square planar arrangement. A new lattice Monte Carlo method based around Fick’s
First Law is also presented. Excellent agreement is found between these quite different methods. It
is also shown that the results are in excellent agreement with the century-old Maxwell Equation.

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作者: Ana Coh O. Hirschmann, Maria do Carmo de Andrade Nono, Cosme Roberto Moreira Silva

摘要: Porous ceramics are of great interest due to their numerous potential applications. The objective of the present investigation was to produce porous alumina with 3 mol % yttria-stabilized tetragonal zirconia (Y-TZP). This material will be used in cooling systems of satellites. To obtain the porous ceramics the direct foaming technique was used. This method is based on the preparation of a stable foam to which a slurry of alumina and zirconia is added. The mixture is then vigorously stirred for incorporation of air. The sintered ceramics were characterized by scanning electron microscopy, mercury porosimetry and thermal conductivity. The tests performed with the porous alumina-zirconia ceramic composite obtained by this method, showed low thermal conductivity values, high porosity and uniform microstructure with 20–100 µm open pores. The results show that the alumina-zirconia composites tested in this study have a potential for application in loop heat pipes of cooling systems of satellites.

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作者: Shi Wei Liu, Jing Kun Yu, Fei Xiong Mao

摘要: Torpedo-ladle was widely used in hot metal transportation. As its insulation properties had deep influence on the quality of iron and steel during the metallurgy process, the method to improve the insulation properties of torpedo-ladle was concerned widely. The results of this paper showed that either using lower thermal conductivity or increasing the thickness of insulation lining could effectively improve torpedo thermal insulation properties by solving the 3-D model with ANSYS.

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作者: Yong Yang, Xue Yu Cheng, Zhao Feng Chen, Ren Li Fu, Zhou Chen, Jing Lian Qiu, Dan Su

摘要: The influence of density on the thermal conductivity of fiberglass felt is studied by experiment.Experimental data obtained using the coefficient of thermal conductivity measuring instrument(Germany Netzsch HFM 436).The results show that the thermal conductivity of the low-density fiberglass felt increases with the increasing of density，when the density of fiberglass felt is below a certain value,the thermal conductivity is tend to a stable value.At last the conclusion that using the heat-transfer mechanism of the porous materials explains this phenomenon has also been drawn by experiment.

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